Add supervised user support

SystemUI also needs also to this activity in order to support
supervised user creation. This activity is temporary and is scheduled
to be removed.

Fixes: 218310361
Test: atest UserSwitcherControllerTest KeyguardUserSwitcherAdapterTest UserDetailViewAdapterTest KeyguardSecurityContainerTest
Change-Id: Ib79dcde2c726cc9508aef667b43662152d047137